1. Field of the Invention
The present invention is generally related to a battery switching circuit for a marine propulsion system and, more particularly, to a switching circuit that responds automatically to changes in the position of a manually controlled mechanism.
2. Description of the Prior Art
Many different types of marine vessels rely on electric storage batteries as the power source for an auxiliary marine propulsion device, such as a trolling motor. In some marine vessels, the propulsion device comprises an internal combustion engine and a related marine drive, such as an outboard motor or a stern drive unit, and an auxiliary drive comprising an electric motor, such as a trolling motor. It is known to those skilled in the art that the internal combustion engine can be used to drive an alternator or generator which provides charging voltage to the electric storage batteries. It is also known to those skilled in the art that the electric storage batteries can be used as a power source for the electric trolling motor or similar marine propulsion device.
U.S. Pat. No. 5,233,282, which issued to Iwashita on Aug. 3, 1993, describes a battery system for a marine propulsion unit. The system is intended for use in connection with a pair of marine propulsion units, one of which is powered by an internal combustion engine that drives a generator and the other of which is actuated by an electric motor. A pair of actuating batteries are in circuit with the electric motor and the generator and are adapted to selectively provide power to the electric motor or receive a charge from the generator in a response to a main switch which is also used to control the starting of the internal combustion engine. A pair of contact relays, responsive to the main switch, are used to adjust the circuitry of the battery system so that the actuating batteries are either connected in parallel in the charging state or connected in series in the actuating state.
U.S. Pat. No. 5,686,819, which issued to Iwatani et al on Nov. 11, 1997, describes a control apparatus for an AC generator of a motor vehicle. The apparatus is of high reliability and has substantially no adverse influence to an outboard battery and an onboard high-voltage load by suppressing to a passable minimum variation of a regulating voltage which may occur as contacts of a detection voltage change-over switch are degraded. An AC generator of a motor vehicle includes a rectifier circuit for rectifying an output of the AC generator including a field coil, an output changeover switch for changing over an output of the rectifier circuit to either one of a battery and a high-voltage electric load mounted on the motor vehicle, and a voltage regulator for regulating an exciting current supplied to the field coil in dependence on a terminal voltage of the battery as detected on a charging line connected to the battery by way of the output change-over switch upon charging of the battery from the output of the rectifier circuit, to thereby regulate the output voltage of the AC generator.
U.S. Pat. No. 5,107,198, which issued to Meyer et al on Apr. 21, 1992, describes an apparatus for charging a battery in a motor vehicle with a self-exciting generator. The apparatus for charging a battery is particularly applicable for a motor vehicle and comprises a self-exciting generator. The generator pre-excitation is improved during starting in that an additional relay is triggered via the starter arrangement and the relay connects the battery with the exciting winding via an additional line when starting and improves the pre-excitation. The additional relay contains a delay circuit, so that the pre-excitation is improved via the additional line some time after the starting process. The additional line or current branch can contain the relay switch of the additional relay, a resistor and a diode connected electrically in series and the battery is connected with the exciting winding of the generator when the additional relay is energized. A capacitor can be connected in parallel with the additional relay coil to provide an appropriate time delay.
U.S. application Ser. No. 09/078,976 which was filed by Alexander et al on May 14, 1998, and assigned to the assignee of the present application, discloses a marine vessel docking control system. The docking control system comprises a plurality of thrusters which can, in turn, comprise individual impellers located within tunnels formed in the hull of a marine vessel. The thrusters are controlled in such a way that a manually controlled joystick allows an operator to selectively maneuver the marine vessel by merely positioning the joy stick in the direction that the operator wishes the marine vessel to move. The thrusters can employ internal impellers or propellers located within the individual tunnel-shaped conduits within the hull. A logic circuit or software system automatically converts the hand controlled movements of the joy stick to combinations of thrust for each of a plurality of electric motors so that the combined effective vectors of force provided by the plurality of impellers results in the desired movement of the marine vessel.
The patents described above are hereby expressly incorporated by reference in the description of the present invention.
It would be significantly beneficial if a system could be provided that regulates the circuit configuration of a plurality of batteries so that the batteries are automatically placed in a charging mode circuit configuration when a hand controlled mechanism is in a neutral position, but in a power providing circuit configuration with respect to a plurality of electric motors when the hand controlled mechanism is not in a neutral position but, instead, is in a position that requires power to be provided to a plurality of impellers driven by electric motors.
The battery switching circuit for a marine propulsion system made in accordance with the present invention comprises first, second, and third batteries which each have a positive terminal and a negative terminal. The circuit also comprises a source of charging power such as an alternator or generator that is driven by an internal combustion engine. The internal combustion engine can be part of an outboard motor or a sterndrive marine propulsion system. It further comprises a manually controlled electrically operated device having an active state and an inactive state. In a preferred embodiment of the present invention, the electrically operated device is a boat docking system which comprises a controller and a plurality of electric motors which are each provided with a propeller or impeller.
A preferred embodiment of the present invention also comprises first, second, third, and fourth switches that are each selectively connected to one or more of the batteries. A switch controller is provided for causing the first, second, third, and fourth switches to be placed in a first condition when the manually controlled electrically operated device is in the inactive state and for causing the first, second, third, and fourth switches to be placed in a second condition when the manually controlled electrically operated device is in the active state. In a preferred embodiment of the present invention, the switches are all in their first state when in the first condition, and in their second state when in the second condition.
A preferred embodiment of the present invention further comprises a fourth battery that is used to start the internal combustion engine and is connected with its positive terminal connected to the source of charging power and its negative terminal connected to a point of ground potential so that the fourth battery receives a charge when the internal combustion engine is operating and is available to start the internal combustion engine when needed. The fourth battery and the first, second, and third batteries are isolated by diodes such that the fourth, or engine, battery cannot discharge into the first, second, or third batteries and their load. The fourth, or engine, battery is therefore preserved for engine starting purposes. Also, the diode isolation prevents the first, second, and third batteries from discharging into the fourth battery in the even of a relay or switch failure.
A hand operable control mechanism, such as a joystick, can be connected in signal communication with the manually controlled electrically operated device. The source of charging power can be an alternator or generator driven by the crankshaft of the internal combustion engine.